Shares of Papa John's International tanked Monday, dropping nearly 10 percent the day after its board took measures to prevent founder John Schnatter from buying a controlling interest in the company.

The price of a share fell by $5.03, closing at $46.56 on Nasdaq and approaching the company's 52-week low of $46.06. The 52-week high is $81.09.

Papa John's, the world's third-largest pizza chain, has struggled for months as customers sought lower-priced brands. Now it is dealing with the fallout from Schnatter's use of a racial slur during a media training session in May and negative articles about the Louisville company's "toxic culture."

Chris O'Cull, managing director of the Stifel Financial Corp., Monday cut his rating from "hold" to "sell" and told clients the outlook for Papa John's "is growing dimmer with recent media reports citing a fraternal corporate culture that is reinforcing consumer perception that Papa John's is not a trusted brand."

In other developments Monday:

• Northern Kentucky University announced it is kicking Papa John’s out of its food court.

University President Ashish Vaidya said “recent remarks by the founder of the pizza chain Papa John’s are offensive, hurtful and unacceptable and do not reflect the core values of NKU.” She said NKU requested that its external food services partner, Chartwells, remove the franchise from its campus.

But Papa John’s will remain on campus at three other public universities in the commonwealth. The University of Kentucky and Western Kentucky University have left that call up to their vendor, Aramark, which has no plans to remove the restaurants.

A spokesman for Philadelphia-based Aramark referred questions to the university but the company told WKU’s College Heights Herald last week that “management and employees at the Papa John’s locations that we operate fully adhere to the diversity and inclusion principles specified by Aramark and those specified by our client partners.”

At the University of Louisville, the name Papa John’s has been removed from Cardinal Stadium but a Papa John’s remains in the Student Activities Center, and its products will still be served at the stadium, university spokesman John Karman said.

“We make a distinction between Mr. Schnatter, who made the offensive comments, and Papa John’s, a locally based company that employs 120,000 people (including franchise stores) and helps support their families,” Karman said. Murray State, Morehead State, and Eastern Kentucky universities don’t have a Papa John’s on campus.

• Experts said Papa John’s International won’t be able to remove Schnatter from the board, and that unless he leaves voluntarily, he will remain as a director at least until its next annual shareholders’ meeting in May.

Under the law in Delaware, where Papa John’s is incorporated, only shareholders — not the board — can vote to remove a director, said Lawrence Hamermesh, a professor emeritus of corporate law at Widener University’s Delaware Law School.

Given that Schnatter owns nearly 30 percent of the shares, such a vote is unlikely, but the board could decide not to renominate him, Hamermesh said.

Schnatter's lawyer, Patricia Glaser, has told the board that he will fight any removal effort.

• Papa John’s directors announced late Sunday that they had approved a plan to block Schnatter from buying a controlling stake in the company. The board adopted what is known as a "poison pill," which makes such a move prohibitively expensive.

"The adoption of the Rights Plan is intended to… protect the interests of the company and its stockholders by reducing the likelihood that any person or group gains control of Papa John’s through open market accumulation or other tactics without paying an appropriate control premium," the company said in a statement.

A poison pill gives shareholders the right to buy more shares at a discount if one shareholder buys a certain percentage or more of the company's shares. If every other shareholder is able to buy more shares at a discount, such purchases would dilute the bidder's interest, making them disinclined to pursue a hostile bid.

Schnatter resigned as board chairman after Forbes reported that Schnatter used the N-word during a media training session in May.

Schnatter publicly apologized for the incident but said later he made a mistake in resigning. He also charged that the board forced him to step down without conducting an investigation of what happened.

The company announced last week that a special committee of board members had hired the Washington-based international law firm of Akin Gump Strauss Hauer & Feld to oversee an audit and investigation of the company that will examine all "existing processes, policies and systems related to diversity and inclusion, supplier and vendor engagement and Papa John’s culture."